A camera-incorporated videotape recorder, which is an apparatus for recording a video signal, is used for news coverage and the like because of its portability. In using the video signal recording apparatus of such a type, a recording time is restricted in response to a capacity of a videotape as a recording medium. Therefore, a photographer generally leaves the recording apparatus in a recording standby state until a scene which he/she wishes to record arrives, and switchovers the apparatus to a recording state when the scene which he/she wishes to record arrives to thereby record the desired scene. In the video signal recording apparatus, still pictures serially photographed per a predetermined interval (for example, 1/30 second) are serially recorded on the videotape so that the recording of moving pictures is realized.
Auxiliary information such as a time code and metadata is recorded on the recording medium apart from a video audio signal comprised of an inputted video signal and audio signal of a plurality of channels. The auxiliary information is utilized in a later editing work as information for managing photographed videos and an audio material.
In contrast, it is desired that, in the video signal recording apparatus used for the crime prevention system, animation photographing and the like, the video audio signal is generated through a photographing operation, which is intermittently implemented per an interval longer than the predetermined interval ( 1/30 second) mentioned earlier, and the video audio signal is serially recorded on the videotape in a high-density and high-definition manner.
In the video signal recording apparatus such as the camera-incorporated videotape recorder, in general, there is a time lag from a time point when a recording-start operation is carried out until the recording apparatus is stabled and ready to actually perform the recording with respect to the tape. During the time period, the video audio signal cannot be recorded. Therefore, when the video signal recording apparatus is used in the news coverage and the like, there is a risk that the recording may be performed failing to record a picture or audio at a moment when the photographer wishes to record, in which some scenes to be captured are missing.
Further, the intermittent video photographing for the news coverage, animation photographing, and the like, the photographing is performed by sequentially repeating (photographing, recording)→(photographing, recording halt)→(photographing, recording restart). However, because of the presence of the time lag, the intermittent video photographing provided with relatively large photographing intervals of a few seconds to a few minutes can be performed, while failing to realize the intermittent video photographing provided with relatively small intervals shorter than the time lag, for example, one second or less. Further, a start-up (time required for starting photographing) is different from one recording apparatus to another (time-length error), which depends on an accuracy of each apparatus, and the time lag is variable in the respective apparatuses. Because of the mentioned problems, it is not easy to assure an accuracy in setting the photographing intervals of the intermittent video photographing (in particular, accuracy in setting minimum photographing intervals).
Therefore, an effort to solve the foregoing problems has been conventionally made by means of a technology recited in No. 10-322659 of the Publication of the Unexamined Patent Applications. To specifically describe the technology, a data retaining device comprised of a memory and a memory control circuit is provided between a video signal compressing device for compressing an inputted video signal and thereby outputting the compressed video signal and a recording device for recording the compressed video signal on a recording medium. The video audio signals, which are equivalent to a plurality of frames and a time length equal to or exceeding an amount of time required from the time point when the recording-start operation is carried out until the actual recording with respect to the videotape, are constantly written in the memory, the write and read of the video audio signals with respect to the memory are controlled by the memory control circuit.
According to the foregoing configuration, the video audio signals from the time point when the recording-start operation is carried out or a time point prior thereto until the time point when the actual recording is enabled are temporarily recorded in the memory. Thereby, a content temporarily recorded in the memory can be written in the videotape when the recording apparatus is up for the recording, and the recording can be thus performed without any signal missed out, starting from the video audio signal positioned at the time point of the recording-start operation. Further, according to the foregoing configuration, the video audio signal photographed per an interval shorter than the time lag can be written in the videotape. Then, the video audio signals intermittently photographed with intervals between 1/30 second and approximately one second can be serially recorded.
However, in the described conventional video signal recording apparatus, compression information of the video audio signal outputted from the compressing device is written and read with respect to the memory, while the auxiliary information such as the time code and metadata pertaining to the photographed video audio signal is recorded on the recording medium from a generation source of the auxiliary information by means of the recording device without an intervention of the memory. Because of that, the auxiliary information is unavoidably temporally delayed relative to the video audio signal on the recording medium. Therefore, a relationship between the video audio signal recorded on the recording medium and the auxiliary information is lost, which makes it difficult to effectively utilize the auxiliary information.
The metadata mentioned earlier is information in which an attribute of the video audio material is denoted in detail, an is comprised of photographing terms such as a photographing time, photographing location as a position information by means of GPS, photographer, shutter speed and iris, a type of filter, and photographic sensitivity, and color space information such as gamma, color gamut and the like, and utilized for compilation of a database, an after process, or the like.
Further, the auxiliary information, other than the mentioned, includes a CUE audio signal recorded in a linear track and used for a search operation in a fast forward/fast rewind reproduction. The video audio signal is recorded as a digital signal in a helical track of the videotape as the recording medium, while the CUE audio signal is recorded as an analogue signal in a linear CUE track thereof. Therefore, the CUE audio signal can achieve a high level of reproducibility, and therefore is used for the search operation. The CUE audio signal, as in the case of the other auxiliary information, undergoes a deteriorated accuracy in the search operation at the time of fast forward/fast rewind reproduction when there is any temporal delay relative to the video audio signal.
A main object of the present invention is to record the auxiliary information, such as the time code and metadata, and the CUE audio signal on the recording medium without any temporal delay relative to the video audio signal in the video signal recording apparatus.